int red = 11;
int yellow = 12 ;
int green =13 ;




void setup() {
  // put your setup code here, to run once:

pinMode(red, OUTPUT);
pinMode(yellow, OUTPUT);
pinMode(green, OUTPUT);}
void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(red ,HIGH);
digitalWrite(yellow, LOW);
digitalWrite(green, LOW);
delay(1500);

digitalWrite(red ,LOW);
digitalWrite(yellow, HIGH);
digitalWrite(green, LOW);
delay(1500);

digitalWrite(red ,LOW);
digitalWrite(yellow, LOW);
digitalWrite(green, HIGH);
delay(1500);

digitalWrite(red ,HIGH);
digitalWrite(yellow, HIGH);
digitalWrite(green, HIGH);
delay(1500);
}